Ventilator



May 1, 1951 J. E. JOHNSON VENTILATOR 2 Sheets-Sheet 1 Filed Nov. 6, 1947 INVENTOR.

w; O .v L

ATTORNEYS.

All

y 1951 Y J. P. JOHNSON 2,551,004

VENTILATOR I Filed Nov. 6, 1947 2 Sheets- Sheet 2 IN V EN TOR. d4) P t/OH/VSON ATTORNEYS Patented May 1, 1951 i .i

I 25551,004 mm'rmuon Anfilicaiiiion Noveniber 6, 1947,,ffSefi2'il Nf7844f6 lli claims. (015298-43) 1 2 l This invention relates to TIOOf "ventilators and that is easily instalied, operated and "reptire'd, more particularly to fan "automatically "opening anti that is "economical 'of -manu'facture anti and closing ventilator*responsive"toitheaotionof ruggedandenduring inconstruetion. V a power driven"exhaust fan housed*therein; @ther"olijeets*andadvantages wilr appear from It-is among theobjects' ofmy invention 'to prothe-"followingdescription-"of a preferred 'form-and vide a positive *aoting exhaust vi-inti'lator a: lthe embodiment'of myiinvention,reference being h'ad straight-through "-type for positively *and fforceto the accompanying drawings imwhih Figure 1 fully removing-eoritaminated'ejir and "gases from is a perspective -.-view *of *my ventilator with the a building through the roof thereof .and atiithe top closureg'elem'entsdn open position; Figure '2 same'time'to*provide'a'weaither=tight ciosurefor is a me'dism-' 1ongitudinallsection-of theuppei porsuha ventiiatorwherewith*tofprevent ingress of tion thereof; Figure 3 is-a -perspective View of=my the elements'through the'roof whenthe ventilator 'ventilaitor in its liinged 'open "orinspection posiis in its-closed -position. Another iibject'tdfmy tion;*Figure4 is*a=transversesection-"of thewhoie inventionis"toproviiie,aventiiaitorthatiwcapaiile ventilator inluding the base portion an'dmurb ofmovinga large*volume'of'aiinifumes and ga'ses 16 's'tructu-rvslriown in Figure 1;Figure 5=is"an end at ahig'hwateof *speedfor-suchmeeiis as'u'seover e-Ievation *df the upper *poxtion -0f --my ventilator vats; furnaces, foundry pouringfioors and=-ot1ier with -part of one of the *e'over -'e1ements-=broken industrial "andcommercial:applications'where the "away -to show the -cover looking 1 and supporting need for*removarof fumes and=gasesmay beunore mechanism; *Fi'gureS 'B' -and Tare enlargecksections 'o'r less intermittent. Another*objeotef'myimzenshowing details of the *cover 'loeking meehanism tion is *to "provide =a-weather proof ventilator taken inzthe plan'es of '*the lines 6- 6 and 1- 1 which automatically opens and-o1oses"depending respectively-of Figure 5- and*-FigureWiswgreatly upon the forciblemo-vementofelinorgasesthereenlarged section taken in a. plane through the through, the air blast '"preventin'g :adniission of pivotal "='supp'o1'"-t*of Figure "5 "and "showing tiet-ails rain, snowentzlthe "like v'hiieithe *veritiiatori's of :the swinging pivota'J "support for the --cover 'openand the automaitic 'self closing feaitureiinilementswand'Figure 9 -is an eniargeii setion of suring the -weather"tightness *of' the *veritfieitor 'a portion of Figure l showing the construction of when it 'is 'o-lose'd. the'base poition -antl aiijacent parts.

Another object of *myinvention-isito proiiide'a in *the preferrefl form of my invention iherin ventilatorofrelativelylargeeapacityfor itsize, 3'0 specifieilly illustrated "and described 'my ventithat canbe easiiy mountedion zoofs oftdiifereiit 1a3tor--c0mpfises 5a top part "'I "and base m '2 shapes andconfigurations;andthatfiseasilyeonhingedly connecteditogetherias'alt"3 forzrelaltive trolledas bytheimerefopening'anfl :elosingofia movementas sh'ownjnftFigure 3, when it is [deswitohfforstarting' andstoppingthe'ffan'orpros'iredto inspect, assemble or'repairithepartsin pel-ler-th'ereo'f. Another tobiect"'i's"togprovide a s'ituybuttnormallybeingarranged so 'that'the 1120p power tiriven'ifan ventilator'withfahighcmeasure part-rests squareiy'upon"the":base or bottom p'ai't of accessibilityitothewofking partstheredfffrom as "shown 'in Figures 1 and 4 ;particularly, for thero'of'side of the ventilator, "eliminating {the normarvent'ilaiting"operation. Thertop part Il'is awkwardness-iandhazard ofiisingfladdersforseajfehsu'a'oterized by "2. "pair "of pivotally swingalble fo "to' ah'iheiwv p epairw'anfi 40 preferablyidenti'cal felosure elementsfiE which in maintenance from =within*thebui1'din1g. Another the olosed posi'tiomias'shown espeoiQHyinTigure and more "specific oliject is to' provfde a hinged S proVidea "weather-"tight 'c'overingfforthe .ve'ntiw mounting for movement tofithe'upper'ortweath'er Iator, -"exc1udingfrain,"wind, snow and osleetffrom excluding portion of the ventilator ireiaztive to the' 'room' or-biiilding "on'iwliich'ithe'ventileltorjis the lo-wefbaseandfanhousing parts thereof. mounteot and which'iinthe op'en1 spositi'on,.Figsfl,

Af rthe objec D B flutbmfitic'ny 2 and-'4, afford *a wide, free *and "lear gopening opening and closing ventilator which iis -"aiit0- for'the forcful exhaustofair and gases upwardly maticailly -se1f -1oeking in its "elosed *weather-seah therethrough -'-as in'dueeWby' the "fan-:6; "the flatter ing pos'ition in the'absence =of a fan iniiucew mast being earfied in *the base part '2 and driven by and which 'is 'responsive only to-flie fan blast ezs 0 an eeetnie' motor' l. Each-of'the ilosure members an automatic unlocking' 'infiuenoe, -eX-terna31 air 5 -is pivotaliy supported for b'oth pivotal "and movement l'being infiective in inducing an -unswinging *movement, *"to be more fully "described desirable.opening of thewentilat'or.- f l below, iboiit a longitifdinally extending axis f1! lather ements inolude the provision f'=a ventiwhereby to *be'eWingaBle ffrom the "'el'osed pos"if-: iatorithet is eflicient anii automaiticfin operation; '51; tion' to the w-ifle open *pos'ition in response to shaped, end walls 2!, see Figs. 1, 2 and 5, which end walls carry the axes llJ, see Fig. 8, upon closure elements are releasably secured in closed position. The structure or .body 20 of the upper portion of the ventilator also comprises vertical side walls 22 of limited height, see Figure '4. The

vertical side and end walls of the body structure preferably rise from a lower truncated pyramidal skirt portion 23 sloping outwardly and downwardly from the vertical walls 2| and 22 and terminating .in a lowermost rectangular vertical skirt or band 24. Along one of the lower longitudinal edges of the band are connected the hinges 3 about which the whole of the upper portion may be swung from its normal operating position to the position shown in Figure 3 when it is desired to gain access'to the interior of the ventilator. The lower wall or skirt 24 on the longitudinal portion opposite the hinges 3 preferably also carries brackets 4 which are adapted to coact with studs 4a and nuts or wing nuts, not shown, in order to secure and support this edge of the skirt 24 to the bottom portion 2 of the ventilator in its operative position; both-the hinges 3 on the one hand and the studs and brackets on the other hand serve to space the skirt portion 24 and the sloping wall 23 from the adjacent upper portions of the base portion 2 -to-;facilitate the free drainage of rain or-other fluid therebetween as at 25, seeFigure 4.

--The upstanding portions of' the end walls 2| take a generally triangular form and are preferably inturned a little alongtheir sloping upper edges for the sake of, stiffness. The apexes'of the end walls are both notchedas at 26 to receive a small \L-shaped drain trough21, the ends of which extend to and if desirable slightly be y'ond the exterior surfaces of the end walls 2i whereby, to spill rain outwardly over the end walls 2! and prevent'its entry. into [the interior of the ventilator. It will also .be noted that the top longitudinally extending edges of the closure members 5' each have angled flanges 28 which in the closed position of the closure members, see Figure 5, overlie and seat upon the upper edges of the trough 21 throughout the length of the troughand closure members. A continuous support is thus provided for the upper edges of the closure members from end toendof the ventilator and a. fluid tight and freely "draining and weather-proof connection forthe topmost part of the ventilator is provided as well- .Interiorly-of the end walls 2| and carriedby each of them approximately in the vertical median plane of-the ventilator there are provided slotted vertically. extending guides 8, Figs. 2..,and 4. These guides are spaced away a little from :the end walls 2 l respectively and are preferablysecured directly to the end walls at the top belowthe trough 21 and may be conveniently secured to the sloping skirt portion 23 at their lower ends. A pair of links Bisprovided at each ;;dian vertical plane of the ventilator. rubber bottom stop members I4 are also provided to be adjustably secured tothe upper porend of the device, the upper ends of which are pivotally connected to the upper portions of the closure members 5 as at II and the lower ends of which are pivotally connected together on pins [2 which are free to slide in the vertically extending slots [3 in the guides 8. In this manner the movements of both of the closure members; 5 are correlated so that their opening and closing movements will be substantially identical as will be their positions relative to the me- Preferably tions of the'guides 8 wherewith to cushion the stopping of the upward movement of the pins [2 and the lower ends of the links 9 as the closure members swing to their fully open position as shown in'Figure 4. The stops [4 may be adjustably raised or lowered on the guides 8 to limit the movement of the links 9 and thus to control the open position of the closure members 5. As will be described later it is desirable that the closure members in their wide open positions have a tendency to close by their own weight whenever the fan is turned off. The stops l4 must be adjusted to retain this characteristic and yet maintain a wide free opening for the fan blast when the fan is on and the ventilator is open.

Each of the closure members, see particularly Figs. 1, 3 and 4, comprises a main central longitudinally extending arcuate portion l5 and integrally joined or connected quadrant like ends It. When the parts are in their closed positionthe vertical edges of the end l6 lie substantially parallel and closely adjacent each other, see Figures 3 and 5, and their lower edges lie in a horizontal plane. .Upwardly beyond the arcuate portions I5the closure members comprise plane portions joining the arcuate portions and the flanged upper edges 28. The lower and outward parts of the sides of the closure members preferably comprise inclined planar parts which terminate in vertical and flared skirts H; the skirts being spaced outwardly from the adjacent and parallel side Walls 22 of the body 20 sufiiciently to permit the swinging movement of the closure members to take place without bringing the lowermost edges of the skirts I1 into contact with the side walls 22. This spacing also permits moisture to drain downwardly from thelinsides of theclosure members and to pass freely between the closure members and the side walls 22 of the body'structure 20 and downwardly over the exterior of the walls 22 and the skirt of thebody 23-24. The lower edge of the skirt [1 preferably lies in the same horizontal plane as the lower edges of the ends [6. The closure members are preferably formed of sheet metal such as galvanized sheet steel and each of the closures has its side and end parts appropriately joined in water tight or weather-proof engagemen whereby each closure acts as an integral piece of metal which in its configuration and structure is self-reenforcing and is strong enough to easily withstand the forces to which it is subjected in operation.

As will now be described and especially with reference to Figures-2, 5 and 8, the closure members are supported in'a manner which provides for a compound swinging movement having especial coaction with a locking mechanism 30 yet to be described. This movement may be most easily described with reference to the closing movement in which the-major portion of the *movement is :a ipivotalsmovementmibout athe saxis i-l ll. 'ithe imembiers rnearaclo'sed ipositionghowzever, the locking ionechanism -.;eauses the yards 31in first temporarily to swing toutwardly :and (slightly I upwardly and ithen 1: swing ibaok :while ;.at ith'e same time the major pivoting zmovement :continues. 1

As shown-also in FigureiZ "longitudinal rods T01 "axes 40 extend longitudinally :of the ventilator adjacent .the side walls 22 f the;bodyl '2 0 z and vare pre'ferably pivotally= supported inballibearings -M, F'igure 8, carried -by the end walls ;2I iandzeach "of the shaf-ts or axes l it has depending fromlteaoh ofits ends:a linker crank 42 which cranksin turn: carryor: comprise theiswinging .tand closure =supportingaxes 'above mentioned. .The axes H1 are pivotal'ly supported in bearings .or .bushings 43 carried respectively by ztheziendwalls [.6 -=of -the :closure members 1 5 .'.'at ttheir vlower land 'outer o'orners. Appropriate. nutssand lock -wash- 'ersseourefthe partsinthenesired:position. Colslars td locate the shafts-140 longitudinally. When the closure ..members.:are in :their .closed position, as jshown in :Figure l 5, the links 42 "take an .iniolined positionisothatitheaxes will at each end 'of the ventilator .:are :somewhat ;more widely spaced .apart .than the .Ishafts All. .As a .result sgravityitends to swingithe lower portionsiof the -610sures 51towardzeach other; itheimovement of the closure membershowever beingrestrained by oontact' with the upper .edges. of .thevlower sloping portions of the end'iwallsias at 1:8 ;a.little above and outwardly of the location of the axis :40. By ithe" same .token the efieot of igrayityon the clos- 111118 members resists in desirable: and limited deigree the-bodily outwardmovementrof the lower .portions thereof.

,As mentioned above ;I :provide the locking :mechanism 3@ to hold the closure members 5 in .closed {IJ-OSltlOl'l against inadvertent :opening and :'the tendency to open, :rattle or shake around under the influence of external forcesisuch as wind or roof drafts. To this ,end,; as shown more particularly1in Figures 5, 6 and '7, each of the end walls .25 carry apair of. pivota11y supported v rollers'tl which aredisposedtolie nearlthe'lower portions of the vertical edges ofthe ends 116 of theclosure members whenfthelatter are'in'their closed :position. Juxtapose'd'toie'ach"of the rollers 3! there is carried by each of'the closure ends it 'a 'cam or locking block saw-men has'suffici'ent thickness to underlie and have bearing "contact witha juxtaposedroller -31. Each of the blocks 32 has a substantially horizontal upper surface 33 and has an inclined forward face "34. These faces intersect at a'corner 35. The result is that when the closure .members swing' downwardly' to 'it'heir :closed positions the lower portions @of ithe faces 34 of the blocks 32 contact the'wupperiand :outward portions of the rollers13l ;and.- oause the aaxes ill and the lower portions ;ofithe;;cover:m'em :.bers"to swing outwardly and slightly upwardly, as viewed in Figure 5, as theytare permitted :.to -d.o b ythe swinging ofthe'cranks 42 aboutithe taxes 40. As the closure members .continne rto swing downwardly toward their closed position .the inclined faces 3 of rthe'blocks V32 cause t'he axes l9 and the lower portions of :the closing :members to swing increasingly outwardly; spread- :ing'the axes i ii fartherandiarther apart. when the corners of the blocks v33-roll below-the'cenrtersof rotation of the rollers .3 then-ras gravity induces 'further 'dQWIlWdId1'Ii1Ql/T6l'i1fllfili :oi zlthe gclosure members the axes :l 9 and :thezlower T1001"- ltions of -i-the closure= members will :start za sanomi back ztoward reaich [other anll this :return :-move :of fohe closuremembers'requires as a prerequisite I uzhespreading ;and:lifting of the axes Ill and the -'-1ower:portions of: theclosurermembersiaway from ieaohaother far enoughito allow the .corners 35 of ztherblooks 32 topass aroundtherollers 3|. .After the 1 corners 1 35 :have :cleared. the rollers, -:the winwolined facesi'35 move eupwardly :and. allow the axes: H1 "1130 return-inwardly. The Y remaining.;ma- -jor :portion :of :the opening movement consists :;primari1y in pivotal movement about the axes J0 althoughperhaps lateraland upward thrust upon ithe closure members may result 1111 801119 swingiing lofat'he cranks-42. This latter mode of operation of the locking mechanism isachieved auto- ;matica-lly-by the building up of air pressure-with- ;i-n the :;upper ;portion -.of the ventilator :by 'the :operation of the fan 6,-but. in the'absenceiof the :magnitude of -air;pressurexthat is .developedby -theranthe closures are held in 'their'snugdownward'japosition with the blocks 32' underlying :the rollers 31 and with'the :olosures bearing :on the endswalls la't about the;point tsu=nearztheir lower outer-edgesand:bearingon theend wallsrinetheir upper inner portions at'thepoints -l-9randxhaving the flanges 28 overlying, reaching inzandzhaving contact with the trough r2? at the extreme top.

;In this -closed and locked position the closures rare snuglyheldand securely positioned withreqspecttorthebodyiw of the ventilator so that they "are restrained against rattling and/or vinad vertent opening by the influence of external .air movements 'and influences.

The bottom partuof the ventilator hingedly .supportingas itdoes the upperpartby thehinges '3 andthe studs 4a andalsosupporting the: fan 6 :andrmotor 1 comprises an nppersheet or deck so having "a central circular opening coaxial or itherfansaxisrwith an upstanding annular ifian'ge 151, see Figs...3 and 4, defining'an opening of diameter rp-referably -slightly greater than the dia- -metrical ilength of i'the ifan .blade. The :deck :or zshellrSfi: is preferably substantially :horizontal and :has its outer rectangular :edge overlying :and rprei'erahly tintetgra'lly :connec'ted :with the upper sedge of :the rectangular :wall15l2 of the base or bottom part 72 :D'f the'ventilator. It'w'ill'be re- :called that theilower 'skirti portion 2324 of "the ?top portionoverlies and is spaced from the upper :part 101 "thetbase part of 'thewentilator as at 2-5 :with :the :result fthat :any moisture J that is :either :thrown from the :fan Jor the fan .iblast or i that otherwise enters the ventilator and tends tocol- 516013.011 the deck WilLiSiIICB it is restrained from drainingfinwardly towardtheffan opening by the :annular ifiange 5|, drain outwardly from the ventilator through the space '25. Likewise .mois- --ture'whioh wets the interior walls of the body 20 :will :also :drain sout'ithrough'tthe opening "25.

i'Preferablyitheiwall :52 risesfrom' an integrally stormed enlarged zandstepped'or shouldered lower part aor ;base portion "which is adapted to rest upon rtherflashzover lthecourbing orifoundation 53 itoiswing H5 nnswhich'ithe ventilatoriasa whole Fis :mouritei'l.

ass-1,004

'Interiorly'the wall 52 at or near the upper portion thereof preferably carries a mounting flange which may take the form of an inturned angle turn by suitable means of attachment, not

shown, carry the motor supporting frame 56 and the fan cowling 51. Preferably the frame 56 supports and affords a vertical mounting plate 58 to which the motor is removably secured by mounting bolts 59 so that the fan and motor may be raised bodily upwardly through the central opening in the deck 50 by detaching the motor from its vertical mounting plate 58. Similarly when the ventilator is in its position open for repair, as shown in Figure 3, with folding struts 60 holding it in that position the fan and motor may be detached one from the other and/or other repairs or replacements made from Without the ventilator with much convenience and facility and without the hazard of operating from the interior of the room or building with the necessary ladders, scaffolding and the like required for such purpose. The struts 60, as shown in Figure 3, are connected to and pivotally supported with respect to the deck 50 at their lower ends and the interior of the body 20 of the upper portion of the device and act to hold'the parts in the position shown in Figure 3 in a familiar fashion while permitting the lowering of the upper portion down to its normal operating position by bending the struts at their middle pivot points.

When the ventilator is in its operative and closed position with the upper and lower parts secured together in their working relation and a with the closure members 5 in their closed and locked position, then energization of the motor I and the rotation of the fan 6 builds up air pressure in the upper portion of the device to effect the unlocking and. opening of the closure members 5 in the manner above described. It may be noted in passing that the end walls [6 of the closure members rather closely overlie the end walls 2| of the upper portion of the ventilator and that the lower inclined parallel portions of the closure members adjacent the points I8 lie close to or snugly upon the upper edges of the side walls 2-2 of the upper body portion of the ventilator and that the extreme upper edges of the closure members have a close fit with the trough 21 so that egress of air from the interior of the ventilator when the same is in its closed position is much restricted in comparison with the capaciy of the fan to move air thereinto whereby an appreciable pressure will be developed interiorly of the closure members to bring about the release of the lock to initiate the opening thereof. The arcuate shape of the closure members appears to facilitate the pocketing of air therein when the same are in the closed position and appear to develop the desirable horizontal components of force incident to the unlocking of the closure members. After the aerodynamic unlocking of the closure members the air blast taken with the configuration of the closure members and especially the arcuate portions thereof maintains the closure members in their wide open position against the .tendency of gravity and the'influences of ex- ,ternal drafts and air:movements which might otherwise tend to close them. The links 9 ccacting with the guides 8 perform the functions above mentioned and also perform an equalizing function or rather an equalizing and balancing function. For example, an external force such as a roof air current which bears on one of the closure members and tends to close it will in more or less corresponding degree act on the other closure member so as to tend to open it. However the members cannot have independently opening and closing movements by reason of their connection with the links 9 and guides 8. These tendencies are thus balanced out and neutralized. It is therefore only from the inside of the ventilator that effective forces can be exerted and consequently the air blast from the fan tends to have exclusive control over the closure members.

It will also be noted that my ventilator as a whole lends itself to economical sheet metal construction for the major portions thereof, exceptions being recognized as to the shafts, guides, links, axis, frame, motor, fan and the like.

While I have illustrated and described a preferred form and embodiment of my invention, changes, modifications and improvements therein will occur to those skilled in the art who come to understand the fundamental principles and advantages thereof and I do'not care to be limited in the scope of my patent to the form herein specifically illustrated and described other than by the claims appended hereto.

I claim:

1. In a ventilator having a base member with an opening, pneumatically actuable closure members having their outer and lower portions pivotally supported on spaced axes and having their upper and inner edges proximate in closed position and movable to positions above said axes in open position, parts of said closure members lying at approximately the level of said axes and spaced therefrom, and locking mechanism associated with said parts comprising elements carried by said parts and movable therewith and coacting elements mounted on said base, said elements being superposed and in contact when said members are closed and coacting to resist opening movement of said members about said axes, said elements being disengageable upon movement of said parts toward said axes, said closure members in their closed position being movable in response to interior pneumatic pressure to move said parts toward said axes.

2. A power actuated ventilator comprising a base, a fan, closure members movable to open position in response to the pneumatic influence of said fan, means supporting said members for swinging and pivotal movements including an axis fixed on said base and an axis movable with respect to said fixed axis secured to each of said ,members, and a locking mechanism comprising coacting latching parts mounted on said members and on said base requiring an initial bodily movement of said closure members relative to said fixed axis to unlatch said parts before permitting an opening movement of the members primarily about said movable axis.

3. A ventilator according to claim 2 in which said initial movement comprises pivoting about the movable edges of said members.

4. A ventilator comprising the combination of a base member, a fan mounted on said base member, a closure member pivotally mounted on a swinging axis supported by said base memher and movable in response to the pneumatic pressure developed by said fan, and locking mechanism for said member comprising one element movable with said member and another element mounted on said base and fixed in relation to said axis in a plane approximately tangent to the arc of operative movement of said swinging axis,

said elements engaging each other transversely of said tangent when said member is in its closed position and preventing direct opening movement thereof, said member, axis and said one element being pneumatically movable in approximately the direction of said tangent to effect disengagement of said elements.

5. The combination of claim 4 in which said swinging axis is disposed to rise against gravity during the disengagement of said elements.

6. The combination of claim 5 in which one of said elements comprises a roller and the other block having acutely angled surfaces successively engageable with said roller.

'7. In a ventilator the combination of a stationary body with spaced end walls having edges inclined from the vertical, a shaft journalled in said walls near the lower ends of said edges, links depending from said shaft adjacent said walls, axes carried by said links swingable with respect to said shaft, movable closure members overlying "the said edges of said walls and having end portions parallel to said walls disposed exteriorly thereof and pivotally supported on said axes, and locking mechanism comprising parts carried by said walls and portions between which relative locking and unlocking movement is effected with the swinging of said axis relative to said shaft.

8. In a ventilator a body member having side walls of limited height and end walls having inclined converging upper edges rising from approximately the top edges of the side walls, a drain trough overlying and supported by the uppermost parts of said end walls and disposed to spill fluid over the exterior of said end walls, movable closure members supported for pivotal movement on axes parallel to said side walls and transversely of said end walls, means for pivotally supporting said closure members on said axes, said closure members overlying the upper edges of said end and side walls at least in closed posi- :tion and having end portions overlapping said end walls and supported by said pivotal supporting means, the upper edges of said closure members being inturned and lying within said trough in the closed position of said closure members.

9. In a ventilator a body member having side walls of limited height and end walls having inclined converging upper edges rising from approximately the top edges of the side walls, a drain {trough overlying and supported by the uppermost parts of said end walls and disposed to spill fluid over the exterior of said end walls, movable closure members supported for pivotal movement on axes parallel to and adjacent said side walls, means for pivotally supporting said closure members on said axis near the upper edges of said side walls, said closure members overly- :ing the upper edges of said end and side walls at least in closed position and having end portions overlapping at least the upper parts of said end walls and supported by said pivotal supporting means, the upper edges of said closure members being inturned and lying within said trough in the closed position of said closure members and the lower edges of said closure members overlapping and spaced from said side walls.

10. A ventilator comprising a base part supporting a housing, an exhaust fan, a top part attached to said base having walls partially over lapping the walls of said base part and spaced therefrom, closure members hinged adjacent their outer edges to the walls of said top part, said closure members having end walls and side walls which partially overlap the walls of said top and are spaced therefrom and having flanged top edges and a longitudinally extending drain trough in which the top flanged edges of said.

\closure members are adapted to lie when the closure members are in closed position, said trough being adapted to conduct liquid exteriorly of said top part.

11. The ventilator of claim 10 in which said base part has a deck with an upwardly flanged opening through which the blast from said fan passes, said deck lying flush with the top of said base part and draining away from said flanged opening and under the said overlapping walls of the top part.

' JAYlP. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 544,390 Shannon Aug. 13, 1895 951,508 Millman Mar. 8, 1910 1,040,360 Lee Oct. 8, 1912 1,222,394 Grimes Apr. 10, 1917 1,291,184 Schulz Jan. 14, 1919 1,503,915 Posner Aug. 5, 1924 1,532,635 Osbun Apr. '7, 1925 1,695,502 Parsons Dec. 18, 1928 1,831,800 Bales et al Nov. 17, 1931 2,141,923 McMahan Dec. 27, 1938 2,295,451 Davis, Jr., et a1. 1 Sept. 8, 1942 2,439,271 Shaver Apr. 6, 1948 FOREIGN PATENTS Number Country Date 93,817 Austria Aug. 10, 1923 56,536 Switzerland Feb. 28, 1911 

